The present invention is generally related to apparatus for grinding and granulating various types of waste material which may contain hard to grind stray materials, and in particular, to an adaptation to a materials processing system which is adapted to protect the grinding and driving components of the system from damage when such hard to grind stray materials becomes trapped or jammed within the grinding components.
In conventional apparatus configured for the processing of material by grinding, shredding, or crushing, there is a constant problem associated with the intake of material which is either to large or to hard for the apparatus to effectively reduce. Such material, commonly referred to as “tramp material”, can become trapped or jammed within the grinding, shredding, or crushing components, resulting in severe damage or destruction to these components or any associated drive mechanisms before the driving motors can be shut down. The high operational speeds of conventional material grinding, shredding, or crushing apparatus make it especially difficult to timely shut down the driving motors when such tramp materials are encountered.
One solution to which reduces the risk of damage to the grinding, shredding or crushing components of a materials processing apparatus is set forth in U.S. Pat. No. 5,743,472 to Williams, Jr. et al. The '472 Williams, Jr. et al. patent discloses an electrical safety cutoff circuit means which is operative upon the loss of a shear pin support means for a sizing screen and shredding cutter for stopping the electrical current supply to a drive motor of the materials processing apparatus. Essentially, the '472 Williams, Jr. et al. patent discloses an automatic cutoff system for the drive mechanism of the materials processing apparatus which is triggered by the loss of a shear pin support means due to trapped or jammed tramp material exerting an excess load on the sizing screen. In the '472 Williams, Jr. et al. system, once the shear pin support means is lost, tripping the electrical safety cutoff, the materials processing apparatus is completely shut down until an operator manually replaces the lost shear pin and restarts the system. This can result in a significant interruption in the materials processing system, due to the time required to replace the shear pin and re-start the associated materials feed systems, drive systems, and processed materials removal systems.
Accordingly, there is a need in the industry for an apparatus which is adapted to protect the grinding and driving components of a materials processing system from damage when such hard to grind stray materials becomes trapped or jammed within the grinding apparatus, and which is capable of being automatically reset, thereby eliminating the need for an operator to manually replace frangible parts and restart the system.